Add active slice handoff contract

server.js

@@ -1396,7 +1396,41 @@ function handoffReadinessFor({ ranked = [], provenance = {}, warnings = [], expe
   };
 }
 
-function copyableHandoffText({ ranked = [], provenance = {}, decisionContext = {}, readiness = {} }) {
+function activeSliceFor({ ranked = [], provenance = {}, readiness = {} }) {
+  const active = ranked.find(item => item.lane?.id === 'do') || ranked.find(item => item.lane?.id === 'test') || ranked[0] || null;
+  const heldBack = ranked.filter(item => item.id !== active?.id && ['test', 'defer', 'park'].includes(item.lane?.id)).slice(0, 4);
+  if (!active) return null;
+  return {
+    schema: 'ranker-active-slice-v1',
+    item: {
+      id: active.id,
+      title: active.title,
+      lane: active.lane?.id || 'do',
+      laneLabel: active.lane?.label || 'Do first',
+      reason: reasonFor(active),
+    },
+    proof: {
+      nextStep: nextStepFor(active),
+      evidenceQuestion: evidenceQuestionFor(active),
+      successSignal: successSignalFor(active),
+      killSignal: killSignalFor(active),
+    },
+    source: {
+      artifactId: provenance?.artifactId || '',
+      conceptMapId: provenance?.conceptMapId || '',
+      snapshotTitle: provenance?.snapshotTitle || '',
+      sourceSection: active.provenance?.sourceSection || '',
+      sourceId: active.provenance?.sourceId || '',
+      sourceTitle: active.provenance?.sourceTitle || '',
+      sourceQuote: active.provenance?.sourceQuote || '',
+    },
+    notNow: heldBack.map(item => ({ id: item.id, title: item.title, lane: item.lane?.id || 'defer', reason: reasonFor(item) })),
+    readinessStatus: readiness?.status || '',
+    rule: 'Only this active slice is build-ready. Do not promote Validate next / Defer / Park items until evidence changes and Ranker is rerun.',
+  };
+}
+
+function copyableHandoffText({ ranked = [], provenance = {}, decisionContext = {}, readiness = {}, activeSlice = null }) {
   const lanes = [
     ['do', 'Do first'],
     ['test', 'Validate next'],
@@ -1438,11 +1472,20 @@ function copyableHandoffText({ ranked = [], provenance = {}, decisionContext = {
       '',
     ];
   });
+  const activeSliceLines = activeSlice ? [
+    '## Active slice',
+    `- Move: ${activeSlice.item.title}`,
+    `- Proof: ${activeSlice.proof.nextStep}`,
+    `- Evidence question: ${activeSlice.proof.evidenceQuestion}`,
+    activeSlice.source.sourceSection ? `- Source: ${[activeSlice.source.sourceSection, activeSlice.source.sourceId].filter(Boolean).join(' · ')}` : '',
+    activeSlice.notNow.length ? `- Do not start yet: ${activeSlice.notNow.map(item => item.title).join('; ')}` : '',
+  ].filter(Boolean).join('\n') : '';
   return [
     '# Ranker build-order handoff',
     sourceLine ? `Source: ${sourceLine}` : '',
     sourceContextLine,
     readiness?.status ? `Readiness: ${readiness.status} — ${readiness.summary || ''}` : '',
+    activeSliceLines,
     contextLines.length ? ['## Carried context', ...contextLines.map(item => `- ${item}`)].join('\n') : '',
     ...itemLines,
     'Rule: only the Do first item is active. Re-rank after evidence changes; do not quietly turn this into a workspace/dashboard backlog.',
@@ -1479,6 +1522,7 @@ function createHandoffContract({ ranked, provenance, decisionContext }) {
   });
   const uniqueWarnings = [...new Set(warnings)];
   const readiness = handoffReadinessFor({ ranked, provenance, warnings: uniqueWarnings, expectsSourceTrace });
+  const activeSlice = activeSliceFor({ ranked, provenance, readiness });
 
   return {
     schema: 'rank-feedback-result-v1',
@@ -1503,7 +1547,8 @@ function createHandoffContract({ ranked, provenance, decisionContext }) {
     itemTrace,
     warnings: uniqueWarnings,
     readiness,
-    copyableText: copyableHandoffText({ ranked, provenance, decisionContext, readiness }),
+    activeSlice,
+    copyableText: copyableHandoffText({ ranked, provenance, decisionContext, readiness, activeSlice }),
   };
 }